Method for suppressing the dehydrogenation activity of deposited metals on inert solids in heavy oil pretreatment

Abstract

Contaminant metals in hydrocarbon oils such as nickel, vanadium and iron deposit on inert sorbents during pretreatment of the oils in a fluidized reactor-regenerator system, and catalyze dehydrogenation reactions contributing to excessive coke and gas make. The dehydrogenation activity of the said contaminant metals is suppressed by depositing minor amounts of a bismuth-containing passivating agent on the inert solids, desirably, at a weight ratio of bismuth to nickel equivalents (nickel+0.2 vanadium+0.1 iron) of about 0.01:1 to about 1:1. The passivating agent can consist of mixtures of compounds of bismuth and antimony, and bismuth and tin, with the weight ratio of bismuth to antimony in the range of about 0.01:1 to about 100:1, and weight ratio of bismuth to tin in the range of about 0.01:1 to about 100:1.

What is claimed is: 
     
       1. A process for the pretreatment of hydrocarbon oil feed which comprises contacting a hydrocarbon feed containing metal contaminants, including nickel, with an inert, sorbent material in a fluidized reactor zone and regenerating said sorbent in a regeneration zone, with circulation of said sorbent between the reactor zone and said regeneration zone, so that the two zones operate as an integrated system; the improvement which comprises: introducing said sorbent into said process, wherein said sorbent contains a composition for mitigating the dehydrogenation reactions caused by the deposition of the contaminant metals on the inert sorbent material during heavy oil pretreatment, said composition comprising a bismuth compound or mixtures of bismuth compounds, in a weight ratio of introduced bismuth to nickel equivalents of between about 0.01:1 and about 1:1.   
     
     
       2. The process of claim 1 in which said inert, sorbent is selected from the group consisting of alumina, synthetic silica-alumina and clay, and has a microactivity for cracking of 20 or less. 
     
     
       3. The process of claim 1 wherein said hydrocarbon feed contains at least 1 ppm nickel equivalents. 
     
     
       4. The process of claim 1 wherein said circulating sorbent is removed at a rate of about 0.5 to about 25 percent of the total inventory per day and replaced with fresh, essentially non-contaminated/sorbent. 
     
     
       5. The process of claim 1 in which said bismuth compound is an organic compound soluble in said hydrocarbon feed or capable of forming a colloidal suspension in said hydrocarbon feed. 
     
     
       6. The process of claim 1 in which said composition is introduced into the regeneration zone of the pretreatment system as solids, in admixture with fresh make-up solids. 
     
     
       7. A process for the pretreatment of hydrocarbon oil feed which comprises contacting a hydrocarbon feed containing metal contaminates, including nickel, with an inert sorbent material in a fluidized reactor zone and regenerating said sorbent in a regeneration zone, with circulation of said sorbent between the reactor zone and said regeneration zone, so that the two zones operate as an integrated system; the improvement which comprises: introducing into said process said sorbent and a composition for mitigating the dehydrogenation reactions caused by the deposition of the contaminant metals on the inert sorbent during said pretreatment, said composition comprising a bismuth compound or mixtures of bismuth compounds, in a weight ratio of introduced bismuth to nickel equivalents of between about 0.01:1 and about 1:1.   
     
     
       8. The process of claim 5 or 7 in which said composition is selected from the group consisting of bismuth compounds, mixtures of bismuth compounds, mixtures of bismuth and antimony compounds, and mixtures of bismuth and tin compounds. 
     
     
       9. The process of claim 7 in which said composition is introduced separately into said pretreatment system. 
     
     
       10. The process of claim 7 in which said composition is introduced into the pretreatment system concurrently with the hydrocarbon feed. 
     
     
       11. The process of claim 7 in which said composition is deposited on essentially fresh solids, and the resulting composition introduced into the pretreatment system. 
     
     
       12. The process of claim 7 in which said composition is admixed with regenerated solids prior to introduction thereof into the pretreatment zone. 
     
     
       13. The process of claim 7 in which said composition is introduced into the regeneration zone of the pretreatment system as solids, in admixture with fresh make-up solids.